An important problem facing stress-strain response modeling of concrete is the complexity of the compressive strength grades. 21 groups of speeimens with different cubic compressive strength （56.3- 164.9 MPa ） hate ...An important problem facing stress-strain response modeling of concrete is the complexity of the compressive strength grades. 21 groups of speeimens with different cubic compressive strength （56.3- 164.9 MPa ） hate beets numerically analyzed. Using only the compressive strength, a stress-strain response model of different concrete grade was established. The numerical simulation model not only qualitatively reproduces the relationship of uniaxial compressive strength, peak value stress and cubic compressive strength, but realizes the consistence of the ascending branch of stress-strain cunts with different strength grades by introducing the correction coefficient k. The results indicate k increases gradually from 0 to approximate 1 with the increase of the compressive strength, corresponding to the transition from the paracurve to straight line branch in stress-strain curves. When k is 0, the madel is identical to the Hognestad equation. A good agreement with the experiment data was obtained.展开更多
Metal−organic framework-derived materials have attracted significant attention in the applications of functional materials.In this work,the rod-like nickel-based metal−organic frameworks were first synthesized and sub...Metal−organic framework-derived materials have attracted significant attention in the applications of functional materials.In this work,the rod-like nickel-based metal−organic frameworks were first synthesized and subsequently employed as the hard templates and nickel sources to prepare the whisker-shaped nickel phyllosilicate using a facile hydrothermal technology.Then,the nickel phyllosilicate whiskers were evaluated to enhance the mechanical,thermal,flammable,and tribological properties of epoxy resin.The results show that adequate nickel phyllosilicate whiskers can disperse well in the matrix,improving the tensile strength and elastic modulus by 13.6%and 56.4%,respectively.Although the addition of nickel phyllosilicate whiskers could not obtain any UL-94 ratings,it enhanced the difficulty in burning the resulted epoxy resin nanocomposites and considerably enhanced thermal stabilities.Additionally,it was demonstrated that such nickel phyllosilicate whiskers preferred to improve the wear resistance instead of the antifriction feature.Moreover,the wear rate of epoxy resin nanocomposites was reduced significantly by 80%for pure epoxy resin by adding 1 phr whiskers.The as-prepared nickel phyllosilicate whiskers proved to be promising reinforcements in preparing of high-performance epoxy resin nanocomposites.展开更多
基金Funded by the National Natural Science Foundation of China(No.59338120) and Doctoral Foundation of Ministry of Education ofChina(No.1999062002)
文摘An important problem facing stress-strain response modeling of concrete is the complexity of the compressive strength grades. 21 groups of speeimens with different cubic compressive strength （56.3- 164.9 MPa ） hate beets numerically analyzed. Using only the compressive strength, a stress-strain response model of different concrete grade was established. The numerical simulation model not only qualitatively reproduces the relationship of uniaxial compressive strength, peak value stress and cubic compressive strength, but realizes the consistence of the ascending branch of stress-strain cunts with different strength grades by introducing the correction coefficient k. The results indicate k increases gradually from 0 to approximate 1 with the increase of the compressive strength, corresponding to the transition from the paracurve to straight line branch in stress-strain curves. When k is 0, the madel is identical to the Hognestad equation. A good agreement with the experiment data was obtained.
基金the Key research and development project in Anhui Province(Grant No.2022i01020016)the National Natural Science Foundation of China(Grant No.51775001)+3 种基金the Anhui Province Natural Science Foundation(Grant Nos.1908085J20,2008085QE269)the University Synergy Innovation Program of Anhui Province(Grant Nos.GXXT-2019-027,GXXT-2020-057)the Natural Science Research Project of Universities in Anhui Province(Grant No.KJ2020A0326)the Leading Talents Project in Colleges and Universities of Anhui Province.
文摘Metal−organic framework-derived materials have attracted significant attention in the applications of functional materials.In this work,the rod-like nickel-based metal−organic frameworks were first synthesized and subsequently employed as the hard templates and nickel sources to prepare the whisker-shaped nickel phyllosilicate using a facile hydrothermal technology.Then,the nickel phyllosilicate whiskers were evaluated to enhance the mechanical,thermal,flammable,and tribological properties of epoxy resin.The results show that adequate nickel phyllosilicate whiskers can disperse well in the matrix,improving the tensile strength and elastic modulus by 13.6%and 56.4%,respectively.Although the addition of nickel phyllosilicate whiskers could not obtain any UL-94 ratings,it enhanced the difficulty in burning the resulted epoxy resin nanocomposites and considerably enhanced thermal stabilities.Additionally,it was demonstrated that such nickel phyllosilicate whiskers preferred to improve the wear resistance instead of the antifriction feature.Moreover,the wear rate of epoxy resin nanocomposites was reduced significantly by 80%for pure epoxy resin by adding 1 phr whiskers.The as-prepared nickel phyllosilicate whiskers proved to be promising reinforcements in preparing of high-performance epoxy resin nanocomposites.
